Resin derived from polyhydric alcohol, fatty oil, benzene tribasic acid and certain glycols



nited States Patent 2,870,102 RESIN DERIVED FROM POLYHYDRIC ALCOHOL,

FATTY 01L, CERTAIN GLYCOLS Richard E. Van Strien, Gritfith, Ind., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application December 16, 1955 Serial No. 553,408 9 Claims. (Cl. 260-22) This invention relates to oil-modified alkyd resins which are suitable for protective coatings. More particularly the invention relates to a process for making oil-modified alkyd resins utilizing tribasic acids.

Conventional oil-modified alkyd resins are made by the polyester condensation reaction of glycerol, oil and a dibasic acid. Suitable resins for protective coating work cannot be made by simple substitution of tribasic acids for the dibasic acids of' the conventional procedure. Tribasic acids are now becoming available in large amounts and protective coatings of characteristics different from the conventional can be obtained utilizing these. Furthermore, the fact that the tribasic acids and anhydrides do not have the relatively low sublimation point .of phthalic anhydride permits reaction conditions of temperatures much higher than those possible with phthalic anhydride. Thus even for equal coating properties it is economically advantageous to be able to utilizetribasic acids and in the preparation of oil-modified alkyd resins.

An object of the invention is an oil-modified alkyd resin utilizing a tribasic acid. Another object is a process for making an oil-modified alkyd resin utilizing a benzene tricarboxylic acid. Another object is an oil-modified alkyd resin suitable for protective coatings made by a process utilizing benzene tricarboxylic acid. Other objects will become apparent in the course of the detailed description of the invention.

An oil-modified alkyd resin is made by a process which comprises (1) reacting a polyhydric alcohol and a member of the class consisting of vegetable oil, marine oil and fatty acids in relative amounts such that essentially only one hydroxyl group in said alcohol remains unreacted, (2) reacting in essentially equi-molar amounts the product of 1 and an acid selected from the class consisting of benzene tricarboxylic acid and anhydrides to form a product containing essentially two unreacted carboxyl groups and (3) under polyester condensation reaction conditions producing an alkyd resin by reacting the product of 2 with a reactant selected from the class consisting of polyhydric alcohols, alkylene polyamines and monoglycerides, wherein said reactant is charged in an amount from about 5 to about 20 mole percent in excess of the stoichiometric requirement.

The first stage of the process of the invention involves the alcoholysis reaction of 'a polyhydric alcohol-and a vegetable oil, marine oil, fatty acid or mixture thereof. The'polyhydric alcohol may be any one of the alcohols which contain at least two hydroxyl groups. Examples of typical polyhydric alcohols which have been used in the preparation of alkyd resins and may be used herein are glycerol, trirnethylol ethane, pentaerythritol, dipentaerythritol, sorbitol and mannitol. Glycerol is preferred.

In addition to these polyhydric alcohols, diols may be used, such as ethylene glycol, propylene glycol, diethylene glycol, 'dipropylene glycol, tetraethylene glycol, etc. Glycerol is preferred as the polyhydric alcohol for use in the first stage'of the process.

The polyhydric alcohol is reacted with one of the oils or fatty acids conventionally used in oil-modified alkyd resin production. The fatty acids utilized may be a BENZENE TRIBASIC ACID AND 2,870,102 Patented Jan. 20, 1950 mixture of fatty acids derived from one of the oils or may be a single one of the various fatty acids. The vegetable oils which are commonly used for this purpose are: linseed, soybean, tung, castor, dehydrated castor, oiticica, cocoanut, cottonseed, rapeseed, perilla, corn, poppyseed, tall, safilower. The marine oils commonly used are: herring, sardine and menhaden.

These vegetable and marine oils are often classified as drying, semi-drying and non-drying oils. Linseed oil is an example of a commonly used drying oil; soybean oil is a typical semi-drying oil; and cottonseed is an example of a non-drying oil. The oils may be processed to obtain a mixture of fatty acids which are designated by the name of the source oil. For example, soya fatty acids are derived from soybean oil. The more or less pure individual fatty acids may also be utilized in the preparation of the composition. Commonly utilized fatty acids are: capric, lauric, myristic, palmitic, stearic, behanic, oleic, linoleic, linolenic, ricinoleic, erucic.

The first stage reaction is carried out utilizing a relative amount of alcohol and oil such that all but one of the hydroxyl groups of the alcohol are reacted; or, conversely, relative amounts such that essentially only one hydroxyl group in the alcohol remains unreacted. For example, one mole of glycerol is reacted with two moles of linseed oil to produce three moles of a diglyceride.

The reaction between the alcohol and the oil in the first stage is carried out under typical alcoholysis conditions. For example, the reaction is carried on at a temperature between about 300 F. and 500 F. under an inert atmosphere for a time such that the desired methanol compatibility is reached.

After the alcoholysis reaction of the first stage has been completed, a benzene tricarboxylic acid or anhydride is added to the product of the alcoholysis reaction. The benzene tricarboxylic acids are trimesic, trimellitic, and hemimellitic. It is preferred to use either the trimellitic acid or the tn'mellitic anhydride. The acid or anhydride and the alcoholysis reaction product are charged in about equimolar amounts, in order to produce a reaction product which contains two unreacted carboxyl groups on the acid molecule.

The second stage reaction is carried out under conditions of time and temperature such as are used in conventional alkyd resin production, although higher temperatures may be used. For example, the second stage reaction may be carried out at a temperature of between about 400 F. and about 500 F. The heating of the two reactants is carried on until a single phase homogeneous solution has been obtained. Preferably the reaction is carried on for a period of a few minutes longer than that needed to obtain a homogeneous solution.

The oil-modified alkyd resin product is obtained by reacting, under polyester condensation conditions, the product of the second stage of the process with a polyhydric alcohol, an alkylene polyamine or a monoglyceride. The polyhydric alcohols may be anyone of the alcohols utilized in the first stage of the process. However, it is preferred to use in the third stage of the process a diol (glycol). Ethylene glycol and diethylene glycol are particularly suitable. In addition to the polyhydric alcohols, alkylene polyamines or a monoglyceride formed by the reaction of glycerol and an oil may be used.

The alcohol, alkylene polyamine or monoglyceride is utilized in the third stage in an amount from about 5 -to about 20 mole percent in excess of the theoretical 3 I 1 action product has the desired viscosity and also the desired acid number.

The oil-modified alkyd resin product of the third stage of the process may then be blended with mineral spirits or with other diluents and also blended with pigments toproduce the particular type of coating material desired for a particular use.

The process of the instant application and the products made therefrom are illustrated by the following examples.

Example I I In the first stage of the process, 35 .0 grams of soybean oil and 1.8 grams of glycerol were added to a flask equipped with a motor-driven stirrer, a thermometer and a reflux condenser. Provisions were made for the maintenance of a nitrogen atmosphere in the flask. The oil and glycerol were heated to 420 F. when 0.1 gram of calcium hydroxide were added as alcoholysis catalyst. The temperature in the flask was gradually increased to about 450 F. over a period of 51 minutes when the reaction was complete.

The second stage of the process was carried out by adding 12.6 grams of trimellitic acid to the flask. The contents of the flask were agitated at a temperature of about 450 F. for one hour and 52 minutes. This time was a few minutes in excess of that time required for the disappearance of the separate phases of alcoholysis reaction product and trimellitic acid and the appearance of a single homogeneous solution in the flask.

The contents of the flask were permitted to cool to 420- F. where 4.1 grams of ethylene glycol were added. In the third stage, the temperature was gradually raised over a period of 40 minutes to 450 F. and maintained at this temperature for 3 hours and 16 minutes.

The reaction product was diluted with 34 grams of mineral spirits to give a solution containing 60% solids, i. e., 60 weight percent of the oil-modified alkyl resin product of the third stage. The Gardner viscosity of the solution was U and the Gardner color was 11. (Physical and Chemical Examination of Paints, Varnishes, Lacquers and Colors by Gardner and Sward, th edition, 1946.)

Example 2 This procedure followed closely that of Example 1 except for the third stage. In the first stage, 35.0 grams of soybean oil was reacted with 1.8 grams of glycerol using 0.1 gram of calcium hydroxide catalyst. The alcoholysis reaction product of the first stage was then reacted with 12.6 grams of trimellitic acid. In the third stage, 4.2 grams of pentaerythritol was added to the second stage product. Only 36 minutes reaction time at 450 F. was necessary to reach the desired viscosity product.

The acid number of the alkyd resin product of the third stage was 34- (mg. KOH/ 100 gr.). The alkyd resin product was diluted with mineral spirits to produce a solution containing 60% solids. The Gardner viscosity of this solution was V and the Gardner color was 11.

Example 3 In the first stage, 35.0 grams of linseed oil was reacted with 1.8 grams of glycerol in the presence of 0.1 gram of calcium hydroxide catalyst. The first stage reaction was carried out at 422 F. for 40 minutes to produce a homogeneous product.

In the second stage, 12.6 grams of trimellitic acid were added to the alcoholysis reaction product and the materials maintained at 445 F. for one hour to obtain a homogeneous material.

To the reaction product of the second stage 16.4 grams of bishydroxyethyl isophthalate was added and the material of the third stage reaction was held for 2 hours and 20 minutes at about 450 F.

The acid number ofthe alkyd resin reaction product was 18. The reaction product was diluted with mineral spirits to obtain a solution containing 60% solids. The viscosity of this solution was Z5-Z7 Gardner.

Thus having described the invention what is claimed is:

1. A process for making an oil-modified alkyd resin which comprises (I) reacting in an inert atmosphere and in the presence of an alcoholysis catalyst a polyhydric alcohol and a member from the class consisting of vegetable oils, fish oil and fatty acids having at least 10 carbon atoms in relative amounts such that essentially only one hydroxyl group in said alcohol remains unre acted, at a temperature between about 300 F. and 500 F. for a time such that the desired methanol compatibility is reached, (II) reacting in essentially equi-molar amounts the product of (I) and an acidic material selected from the class consisting of trimesic acid, hemimellitic acid, trimellitic acid and trimellitic anhydride to form a prodnot containing essentially two unreacted carboxyl groups on the acid molecule, at a temperature between about 400 F. and 500 F; until a single homogeneous solution is obtained and (III) reacting the product of (II) with an alcohol selected from the class consisting of ethylene glycol, diethylene glycol, pentaerythritol and bis-hydroxyethyl isophthalate, wherein said alcohol is charged in an amount from'about 5 to about 20 mole percent in excess of stoichiometric requirement, at a temperature between about 400 F. and 500 F. for the time necessary to obtain the desired viscosity and the desired acid number.

2. A process' for producing an oil-modified alkyd resin which comprises (I) reacting in an inert atmosphere and in the presence of an alcoholysis catalyst about 1.8 parts by weight of glycerol and 35 parts by weight of soybean oil at about 450 F. until the alcoholysis reaction is complete said reaction product being characterized by the presence of essentially only one unreacted hydroxyl group in said glycerol, (II) reacting the product of (I) with about 12.6 parts by weight of trimellitic acid at a temperature of about 450 F. until a single homogeneous solution is obtained in the reaction zone said reaction product being characterized by essentially two unreacted carboxyl groups on the acid molecule and (III) reacting the product of (II) with about 4 parts by weight of ethylene glycol at a temperature of about 450F. until the desired viscosity and acid number is obtained.

3. A process for preparing an oil-modified resin comprising (I) reacting in an inert atmosphere and in the presence of an alcoholysis catalyst about 1.8 parts by weight of glycerol and about 35 parts by weight of linseed oil at a temperature of about 450 F. until the alcoholysis reaction is complete said reaction product being characterized by the presence of essentially only one unreacted hydroxyl group in said glycerol (II) reacting the product of (I) with about 12.6 parts by weight of trimellitic acid at a temperature of about 450 F. until a single homogeneous solution is obtained in the reaction zone said reaction product being characterized by essentially two unreacted carboxyl groups on the acid molecule and (III) reacting the product of (II) with about 16.4 parts by weight of bis-hydroxyethyl isophthalate at a temperature of about 450 F. until the acid number of the reaction product is about 18.

4. The process of claim 1 wherein the alcohol of I is glycerol.

5. The process of claim 1 wherein the oil of I is soybean oil.

6. The process of claim 1 wherein the oil of I is linseed oil.

7. The process of claim 1 wherein the acid of H is trimellitic acid.

8. The process of claim 9 wherein the acid of II is trimellitic anhydride.

9. A composition produced by the process of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,048,778 Brubaker et al. July 28, 1936 

1. A PROCESS FOR MAKING AN OIL-MODIFIED ALKYD RESIN WHICH COMPRISES (I) REACTING IN AN INERT ATMOSPHERE AND IN THE PRESENCE OF AN ALCOHOLYSIS CATALYST A POLYHYDRIC ALCOHOL AND A MEMBER FROM THE CLASS CONSISTING OF VEGE TABLE OILS, FISH OIL AND FATTY ACIDS HAVING AT LEAST 10 CARBON ATOMS IN RELATIVE AMOUNTS SUCH THAT ESSENTIALLY ONLY ONE HYDROXYL GROUP IN SAID ALCOHOL REMAINS UNREACTED. AT A TEMPERATURE BETWEEN ABOUT 300* F. AND 500* F. FOR A TIME SUCH THAT THE DESIRED METHANOL COMPATIBILITY IS REACHED, (II) REACTING IN ESSENTIALLY EQUI-MOLAR AMOUNTS THE PRODUCT OF (I) AND AN ACIDIC MATERIAL SELECTED FROM THE CLASS CONSISTING OF TRIMESIC ACID, HEMIMELLITIC ACID, TRIMELLITIC ACID AND TRIMELLITIC ANHYRIDE TO FORM A PROD UCT CONTAINING ESSENTIALLY TWO UNREACTED CARBOXYL GROUPS ON THE ACID MOLECULE, AT A TEMPERATURE BETWEEN ABOUT 400* F. AND 500* F. UNTIL A SINGLE HOMOGENEOUS SOLUTION IS OBTAINED AND (III) REACTING THE PRODUCT OF (II) WITH AN ALCOHOL SELECTED FROM THE CLASS CONSISTING OF ETHYLENE GLYCOL, DIETHYLENE GLYCOL, PENAERYTHRITOL AND BIS-HYDROXY ETHYL ISOPHTHALATE, WHEREIN SAID ALCOHOL IS CHARGED IN AN AMOUNT FROM ABOUT 5 TO ABOUT 20 MOLE PERCENT IN EXCESS OF STOICHIOMETRIC REQUIREMENT. AT A TEMPERATURE BETWEEN ABOUT 400* F. AND 500* F. FOR THE TIME NECESSARY TO OBTAIN THE DESIRED VISCOSITY AND THE DESIRED ACID NUM BER. 